<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <style>
    * {
      margin: 0;
      padding: 0;
    }
    ul li {
      list-style: none;
      height: 50px;
      flex: 1 1 200px;
      /* flex-shrink: 1; */
      /* flex-grow: 1; */
    }
    /* li:nth-child(2) {
      flex-shrink: 0;
    } */
    ul {
      width: 700px;
      display: flex;
    }
  </style>
  <body>
    <ul>
      <li style="background-color: red">1</li>
      <li style="background-color: blue">2</li>
      <li style="background-color: gray">3</li>
    </ul>
  </body>
</html>
